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So I was looking for a small fairly robust solid state amplifier module to replace a 1980's vintage boom box for playing music in my wood shop. The environment is VERY dusty so sealed enclosures are a must. As such I needed something small, fairly efficient, and easy to work with. So I went to Parts Express and ordered a Sure Audio AA-AB32231 2x8W Class D amplifier module. This module uses a Texas Instruments TPA3110 series chip. The board looks like this:

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So being a typical engineer, I immediately took it out of its box and wired it up. To say I was impressed is an understatement. Here it is just sitting on my desk playing it's first music:

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The sound produced by this little amplifier with just a wall-wart and an iPod input is really quite excellent. Even more so when you realize it only cost $15.98 (USD) each.

The unit from Parts Express comes with screw terminals for inputs, outputs, and power as well as standard power connector and 3.5mm stereo jack. It really is a very nice little module.

In a little box in my shop with a couple of switchable inputs, this is going to make a really nice little amplifier. I'll post some pictures as soon as I get it boxed up.

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Hi, Yes indeed. The current crop of mini class D amps are quite excellent. Cheap, efficient and decent sounding. I only had one with issues. It was a 2.1 version that I wanted to use with a TV. Unfortunately it was not well filtered and put crud on the grounds and in turn the CATV line. I got a visit from the CATV service folks. They tracked it down as it was causing interference on the cable all over the neighborhood. Funny thing is it didn't cause any problems with my gear. Go figure. Needless to say I canned it. Most don't seem to have this problem fortunately. PE has several really good amp modules and I highly recommend them.

The Sure 100W module (about 40W into 8ohms) is a great and cheap standard. I’ve built about 10 Class Ds and a couple with the 100W module. A mate brought his 100W amp around just a few days ago and we compared it with a Lm4780 chip amp (just completed) and my latest 180W Tripath amp (najah) which uses the onboard PS and a 500W potted toroidal.

The Tripath 180W was just better than the other two but the 100W Sure was very close. I felt the bass wasn’t as strong or deep and a touch of over sibilance. From my experience the Tripath Ds have better upper frequency control.

I think with more and more big names in the high end audio game coming on board we are going to see Ds really shine. They are already challenging the Class AB market and with some stereophile reviews making them thier reference amp a genuine change is coming.

Doesn’t mean we sell off out tubers or chippers it just makes the hobby a little more interesting. I have three D amp projects in front of me and then I really just move on. My main power amps for some time now have been Ds. Very happy.

This afternoon I took to putting this little module in a sealed enclosure for my dirty shop. I chose to use a Pamona 4226 enclosure like I used for my "Industrial" 4S preamp. Here is what it looks like.

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Obviously not wired yet, but you get the idea.

I should get it wired up this week when I have some time.

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This amp should work really well in my very dusty workshop. This was one of those little projects you put together with a lot of just what you have on hand. I've decided I'm going to screw this amp to the wall behind my workbench. I'll have an FM tuner under the bench and a cord for my iPod on the back of the bench. I can switch between the two with a flip of the switch.

Overall, I'm very satisfied with how this project worked out.

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I built a number of various D-class amps and built them into nice plastic boxes from German www.reichelt.de. The amps ranging from 3110 up to stuff saying may leave 50W each channel (I don't believ that), but still they do a good job.

The only criticism is that when playing on speakers with a lots of resolution they may sound harsh, but if you have been building DHT SE-amp and suddenly need something for speakers rating an impressive 80dB/W/m, the cheap Chinese D-amps will certainly make your day.

(I bought my amplifier modules at USD3-4 from AliExpress)

(And the PAM8403 cost as litle as 20 cents/each when buying 10 pcs).

_________________Magnus

“If you don't know where you are going, any road will get you there.”―Lewis Carroll

This afternoon I finally got this project installed. Here is a picture of the unit mounted on the wall behind the workbench in my shop.

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The inputs are coming from an old Kenwood KT-59 AM/FM stereo receiver mounted under the bench. I bought the receiver at a local used electronics recycler for $10 USD. I made a little folded dipole out of 300Ω twin-lead for the receiver and it pulls in lots of local stations. The other set of amp inputs will mostly be used with an iPod or cell phone.

This setup sounds MUCH better than the almost 40 year old boom box I had driving my speakers previously. And it really didn't cost much either; less than $50 USD total for everything that wasn't in my miscellaneous parts stash. Overall, I'm very happy with how this turned out. These little class-D modules really fill a nice design niche.

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They certainly can surprise. The Sure 100W module is a good place to start for a more serious genuine hifi setup. I’ve built a number with the module and so has a friend. Up against expensive his (locally made and high-end) Class A/B bipolar amps they still hold their own.

I would image the commercial high end SS amp industry would not want audiophiles to discover how good and how cheap high performance Class Ds can be. It would/will put pressure on them to price their gear more competitively. That would be good for both parties.

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